Method for coating cores



J. S. LITTLE Jan. 25 1 927.

MET HOD FOR COATING CORES Original Filed May 30, 1924 6 Jam 521222?yaw/21m fig,

Patented Jan. 25, 1927.

UNITED STATES PATENT OFFICE.-

Jomi sHInLEY LITTLE, or LA GRANGE, ILLINOIS, ASSIGNOR TOwnsrnmInLEc'rRIo COMPANY, moonronarnn, or new YORK, N. Y., A conronn'nonon NEW YORK.

METHOD FOR COATING CORES.

I Application filed May 30, 1924, Serial No. 716.842. Renewed October20, 1926.

This invention relates to a method for coating cores and moreparticularly to a method for coating cores with pulpous material.

A feature of the invention is the manner in which the pulpous materialis dried upon the cores by subjecting it to air of predeterminedtemperature and predetermined relative humidity.

The pulpous material is preferably applied to the cores by apparatus ofthe type disclosed vin the co-pending application of H. G.. lValker,Serial N 0. 569,751, filed June 20, 1922, which apparatus is adapted tosubject a core in strand form to liquid containing pulp, the pulp beingsubsequently treated to form a homogeneous coating for the core.

In practice itis necessary to dry the pulpous material thoroughly afterit has been applied to the core. This should be. done so that thepulpous material will be retained upon the core and, where the core isan electrical conductor, so that the core will be properly insulated. a

If the pulpous material is dried by subjecting it to a high temperaturewhich tends to withdraw the surface moisture from the pulp very rapidlyand no provision is made to control the relative humidity of the air incontact with the pulpous material, the moisturein the innermost portions"of the pulp coating will not pass readily to the surface of thecoating; the thin shell of dry pulpous material which the inner layer ofmoist pulpous material from the high temperature. The temperature mustbe kept suflici'ent-ly low sothat'the pulp coating will not be injuredor destroyed, but e en if the pulp coating is subjected to a propertemperature and no provision is made to regulate the relative humidityof the air Into which the moisture of the pulp coating is evaporating,it is exceedingly diflicult to produce a uniform article. Under properconditions the pulpous material may be thoroughlydried upon the core inajpredetermined period of time. This insures a uniform'product.

The drawing illustrates the' improved method as employed for coating :1core in strand form. In this instance the core is coated with unfinishedpaper ofwhich the fabrication is completed while it is on the core. Thecore is first brought into intimate contact with a liquid containingpulp Wherems P p is formed tends to protectwhich a core in strand formby pulp is applied thereto. The core is then removed from the pulpmixture, a ribbon of pulp adhering to the core as it is withdrawn fromthe mixture. The free liquid is removed from the pulp adhering to thecore and this pulp is then worked or formed into a uniform coating forthe core, which coating contains an undesirable amount of moisture.The-coating is then dried in circulating air of predeterminedtemperature and predetermined relative humidity.

'The objects of the invention will become more apparent as the detaileddescription progresses, reference being had to the ac companyingdrawings wherein Fig. 1 is a plan elevation partly in section of apreferred apparatus for performing the method embodying the invention,

Fig. 2 isa side elevation, partly in section of the apparatus shown inFig. 1,

, Figs. 3 and t are enlarged transverse sections showing the forming ofa pulp coat-' ing as it is delivered from the liquid containand certainsqueeiingrolls respectively, and,

Figs. 5 and 6 are enlarged transverse sections showing the forming of apulp coating during the'forming operation and after the completion ofthe forming operation respectively.

It is believed that a complete understanding of the improved method Willbe procured from a description ofthe apparatus by which it may beperformed. i

Referring to the drawing, the reference character 10 designates a supplyroll from is drawn over an idler roll 11 and thence around a drum 12which is partly submerged in a liquid containing pulp within a tank 13.

The drum 12 preferably comprises a pair of sides 14 and a peripheralportion 15 interposed between thesides. The portion 15 is provided witha plurality of relatively large perforations .(not shown) which are 1covered with a strip of fine wire mesh 17. The drum has a tubular -axle18 which is rotatably mounted in suitable bearings 19 in a frameworkwhich supports'the tank 13..

The tank is adapted to hold a quantity of 1 maintained at a level lowerthan that of the pulp in the tank A continuous circulation 11.9

of the pulp mixture is maintained by suitable means (not shown) whichinsuresthatpulp in the tank liquid will pass from the 13 into the drum12 through the wire mesh 17 thus straining pulp onto the surface of thewire mesh and onto the core which is trained around the drum. Theapparatus is so arranged that some pulp is first strained onto the wiremesh, before the core is brought into contact therewith. Then when thecore contacts the initial layer of pulp on the mesh and the drumcontinues to revolve in the tank, an additional amount of pulpousmaterial will be deposited on the core and the wire mesh. The core andthe pulp deposited thereon are brought into contact with a felt coveredroll 24 adapted to remove free liquid, from the pulp adhering to thecore and to aid in picking off the pulp from the mesh. A'roll25co-operates with the roll 24to impart a contour to the pulpous materialsubstantially as shown in vFig. 3. The core and its pulpous material arethen drawn between a pair of squeezing rolls 26 which impart a contourto the pulp substantially as shown in Fig. 4 and remove additionalmoisture from the pulp. The core with its ribbon of pulp is then passedthrough a forming mechanism 30 which wraps the ribbon around the core asillustrated in Fig. 5 until the pulpous material is worked into auniform coating conforming to the shape of the core (Fig. 6).

The above described apparatus resembles that shown in the aforementionedco-pending application wherein the apparatus is more fully illustratedand is described. in

detail. The apparatus delivers the core with apulp coating having therequired form but the coating retains an undesirable amount of moisturewhich must be removed therefrom to insure that the coating will remainupon the core and will be of a uniform quality, it beingunderstood thatthe Wet pulpous material is easily stripped from the core and that it isundesirable to have different portions of the coating vary as tomoisture content. It is obvious that if the core is to be employed asanelectrical conductor, the coating should be thoroughly dried to preventfailure thereof I as insulation.

In the preferred embodiment of the invention the pulp coating deliveredfrom the forming mechanism 30 is thoroughly dried by being subjected toair of predetermined temperatur and predetermined relative humidity fora predetermined length of time. The core with its coating is led fromthe forming mechanism 30, through a honilurality of sheaves 33 disposedin the housing 31 lead the coated core through a circuitous path, thelength of which is determined by the speed at which the coated coretravels and by conditions maintained within the housing. Theseconditions, the temperature and relative humidity of the air within thehousing, are held substantially constant with respect to certain'predetermined values.

Any suitable air conditioning apparatus may be employed for holding thetemperature and the relative humidity of the air within the housingsubstantially constant. Thus in the drawing, air conditioning apparatusof a well known type is shown an comprises a fan 35 adapted'to establisha circulation of air through the housing. The fan 35 is disposed outsidethe housing and, when in operation, blows air into the housing byway ofa conduit 36 which terminates in a plurality of nozzles 37 within thehousing. The fan 35 draws this air from an auxiliary housing 38 which isprovided with a conduit'39 communicating with the housin 31, a shutter40 being provided to control the flow of air from the housing 31 intothe conduit 39. The auxiliary housing 38 is also provided with anaperture 42 through which a supply of fresh air is admitted to theauxiliary housing, the flow of air through the aperture shutter 43. Theshutters 40 and 43 are preferably connected by suitable mechanism whichcauses the shutter 40 to open as the shutter 43 is closed and to closeas the shutter 43 is opened,- the shutter 43 being manually controlled.The mechanism which connects the shutter 40 with the shutter 43 isindicated at 45.

A hygrostat 46 and a thermostat 47 are positioned in the path of theair'flowing from the housing 31 into the auxiliary housing 38 by way ofthe conduit 39. The hygrostat 46 controls the relative humidity of theair circulating through the system as it is adapted to control theadmission of steam into the auxiliary housing 38 through the medium of apipe 48 projecting into the auxiliary housing and provided with aplurality of nozzles 49. The pipe 48 is connected to any suitable supplyof steam (not shown) and the hygrostat 46 is adapted to control the flowof steam through the pipe, the hygrostat being operatively connected bya well known means (not shown) to a Valve 50 in the pipe.

The thermostat 47 controls th e flow of steam to a plurality of heaters01. and 52 disposed in the auxiliary housing 38. The

.heaters 51 and 52 are connected to a suitable supply of steam notshown) and the thermostat 47 is operatively connected by a well knownmeans (not shown) to valves 53 disposed in pipes 54. which connect theheaters 51 and 52 with the supply of steam.

The housing 31 is provided with an aperture 56 whereby air may escapefrom "the system, a plurality of shutters 57 being piv- I housing 31below the desired value.

otally mounted in the aperture and being adapted to swing open when thepressure within the housing 31 exceeds the atmospheric pressure.

Inthe operation of the apparatus for drying the pulp coating, theshutter 43 is opened to admit fresh air into the system, the shutterbeing so positioned that 'suflicient air is added continually to thesystem to keep the relative humidity of the air in the air iscontinually added to the system, the

pressure in the housing 31 tends to rise above the atmospheric pressurethen obtaining and the shutters 57 swing open,

thus allowing air to escape from the housing 31 by way of the aperture56. The escaping air serves as a medium for removing moisture from thesystem, it being necemary to provide some means for discharging themoisture evaporated from the pulp coating. It is for this reason thatair' is continually added to and discharged from the system. Thetemperature of air in the housing 31 is held substantially constant bythe thermostat 47 which co-operates with the hygrostat 46 to maintainthe desired conditions in the system.

In practice, it has been found advantageous to maintain a temperature ofapproximately 160 within the housing 31, the relative humidity of theair circulating through the housing 31 being maintained at approximately20%. This allows the ulp coating to become thoroughly dry in a period ofsubstantially four minutes.

What is claimed is:

1. A method ofcoating a core with ulpous material which\ consists in appying moist ulpous material to the core and in subjecting the pulpousmaterial to a predetermined temperature.

2. A methodot coating a core in strand form with. pulpous material whichconsists inapplying moist pulpous material to the core while it is inmotion and in subjecting the pulpous material to a predeterminedtemperature.

3. A method of coating a core with pulpous material which consists inapplying moist pulpous material to a core and in drying the pulpousmaterial in air-of predetermined relative humidity.

4. A method of coating a core in strand" form with pulpous materialwhich consists .This

in applying moist pulpous material to the core while it is in motion andin drying the pulpous material in air of predetermined relativehumidity.

5. A methodof coating a core with pulpous. material which consists inapplying moist pulpous material to the core and in drying the pulpousmaterial in air of predetermined temperature and predetermined relativehumidity.

6. A method of coating a core in strand form with pulpous material whichconsists in applying moist pulpous material to the core while it ismotion and then drying the pulpous material in air of predeterminedtemperature and predeterminedrelative humidity.

7. A method of coating a core with pulpous material which consists inapplying moist pulpous material to the core and then subjecting theulpous material for a predetermined perlod of time, to air of piedetermined temperature and predetermined relative humidity.

8. A method of coating a core' with pulpous material which consists inapplying liquid containing pulpous material to the core, removing freeliquid from the pulpous material, and then drying the pulpous materialby subjecting it to a predetermined ten'iperature. i

9. A method of coating a core, with pulpous material which consists inapplying liquid containing pulpous material to the core, removing freeliquid from the pulpous material, and then drying the pulpous materialin air of predetermined relative, humidity. p 10. A method of coating acore with pulpous material which consists in subjecting the core toliquid containing pulpousn'iatorial so that said pulpous materialadheres to the core, removing free liquid from said pulpous material,and then drying the pulpous material in air ofpredetermined temperatureand predetermined relative humidity.

11. A methodof coatin a core in strand form with pulpous material whichconsists in subjecting the core while it is in motion to liquidcontaining pulpous material so that said pulpous material adheres to,the core, removing free liquid from the core, and then drying thepulpous material in air of predetermined temperature and predeterminedrelative humidity.

12. A method of coating a core in strand nae ing the fabricationincluding the dryin thereof in air of predetermined relative humidity.

14. A method of coating a core in strand form which consists in applyingunfinished paper to the core and subsequently completing the fabricationof the paper on the core including the drying thereof in air ofpredetermined tempe'rature and predetermined relative humidity.

, 15. A method of coating a core with pulpous material which consists inapplying moist pulpous material to the core and in subjecting thepulpous material to circulating air of a predetermined temperature.

16. A method of coating a core with pulpous material which consists inapplying moist pulpous material to the core and in subjecting thepulpous material to circulating air of a predetermined relativehumidity.

17 A method of coating a core with pulpous material 'which consists inapplying moist pulpous material to the core and in subjecting thepulpous material to circulating air of (predetermined temperature andpredetermined relative humidity. .\'18. A method of coating \a corewhich consists in applying unfinished paper to the core and 1ncompleting the fabrication of the paper on the core includingdryingthereof in air of a predetermined temperature.

19. A method of coating a core which consists in applying unfinishedpaper to the core and in completmg'the fabrication of the paper on thecore including drying thereof in air of a predetermined relativehumidity.

20. A method of coating a core which consists in applying unfinishedpaper to the core and in completing the fabrication of the paper on thecore including drying thereof in air at a predetermined temperature andpredetermined relative humidity.

21. A' method of coating a core with ulpous material which consists inapp ying of the paper on the core;

moist pulpous material to the core, and in subjecting the pulpousmaterial to air held at a predetermined temperature which is between 140F. and 180 F.

22. A method of coating a core with pulpous material which consists inapplying moist pulpous material to the core, and in subjecting thepulpous material to air held at a predetermined constant temperatureabove 100 F.

23. A method of coating a core with pulpous -material which consists inapplying moist pulpous material to the core, and in subjecting thepulpous material to air having a predetermined relative humidity of notless than 5% nor more than 24:. A method of coating a core with pulpousmaterial which consists in applying moist pulpous material to the core,and in subjecting the pulpous material to air of substantially constantrelative humidity of not more than 70%.

25. A method of coating a core with pulpous material which consists inapplying moist pulpous material to the core, and in subjecting thepulpous material for from 1 to 8 minutes to air conditioned to have apredetermined characteristic.

26. A method of coating a core With pulpous material which consists inapplying moist pulpous material to the core, and in subjecting thepulpous material to air-for more than 1 minute, the air being held at asubstantially constant temperature which is more than'90 F.

27. A method of coating a core which consists in applying moist pulpousmaterial to the core, and in subjecting the pulpous material to air ofsubstantially constant relative humidity, the pulpous material beingsubjected to the air from 1 to 10 minutes.

In witness whereof, I hereunto subscribe my name this 22nd day of May A.D., 1924.

JOHN SHIRLEY LITTLE.

